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PHEVs release nearly five times greater planet-heating pollution than official data indicate, as per a recent report.

Growing Discrepancy Between Lab and Actual CO2 Output

Data shows that PHEVs release only one-fifth lower CO₂ than traditional gas and diesel vehicles, based on analysis conducted by a non-profit group. This differs significantly with laboratory estimates, which assumed a 75% reduction in emissions.

Analysts studied information from onboard fuel consumption meters of 800,000 cars sold in Europe between 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, up from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” stated a senior researcher participating in the study. “This discrepancy is growing and poses a significant problem. As a result, PHEVs emit nearly as heavily as gasoline cars.”

Key Reasons Behind the Emissions Gap

Researchers linked the majority of the gap to inflated estimates of the “electric driving share” – the percentage of kilometers driven in battery mode relative to total distance. They found that only a quarter of driving was completed in electric mode, whereas lab assumptions suggested over four-fifths.

Additionally, when running in electric mode, pollution amounts were well above lab projections. This occurred because EV motors were not strong sufficient to operate alone, resulting to combustion motors using gasoline for almost one-third of the travel completed in electric mode.

Regulatory and Financial Implications

According to estimates, the lowballing of PHEV emissions enabled four large carmaker groups to escape over €5bn in penalties between 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs would spend about €500 extra annually in running costs than is assumed under laboratory tests.

“The bold claims that manufacturers like to make about their PHEV cars are clearly way off the mark,” commented a transport analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of fuel use, CO₂ emissions, and operating costs.”

Political Debate and Industry Lobbying

Plug-in hybrid cars have lately been brought again into policy discussions as carmakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on new internal combustion cars in 2035 has faced heavy pressure from the car industry and opposition from EU countries with large car manufacturing.

Several high-level politicians have proposed plug-in hybrids as a potential “flexibility” option to include in the regulation.

One independent energy policy expert, who was unaffiliated with the research, called the analysis a “very useful contribution” after years in which segments of the automotive industry argued there was insufficient data to accurately evaluate real-world emissions.

“The results show, without question, that the gap in lab and real-world PHEV fuel consumption and CO₂ output is much, much greater than for petrol or diesel cars,” they said. “Any policy changes regarding PHEVs should be implemented with extreme care and considering this data.”